diff --git a/src/lib.rs b/src/lib.rs
index 8f77bcf..61bec1a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -227,11 +227,15 @@ fn anonymize(text: &str, custom_raw: &str) -> Result<(String, Vec<Redaction>), M
             "IBAN",
             // Match the structural shape, surrounded by word
             // boundaries so we don't slice into longer alnum
-            // strings.
+            // strings. The BBAN body allows an OPTIONAL single space
+            // before each character so the standard grouped spelling
+            // (`DE89 3704 0044 0532 0130 00`) is redacted, not just
+            // the contiguous form — otherwise the leading group leaks
+            // and the phone rule mislabels the rest.
             Regex::new(r"(?x)
                 \b
                 [A-Z]{2}\d{2}
-                [A-Z0-9]{11,30}
+                (?:\s?[A-Z0-9]){11,30}
                 \b
             ").map_err(re_err)?,
         ),
@@ -434,6 +438,23 @@ mod tests {
         assert_eq!(reds.iter().filter(|r| r.kind == "BIC").count(), 1);
     }
 
+    #[test]
+    fn redacts_grouped_iban_without_phone_misclassification() {
+        // The standard German spelling groups the IBAN in 4-char
+        // blocks with spaces. It must redact as a single IBAN — not
+        // leak the leading group while the phone rule eats the rest.
+        let (out, reds) =
+            anonymize("Zahlung an DE89 3704 0044 0532 0130 00 heute", "").unwrap();
+        assert!(
+            out.contains("\u{27E6}IBAN_1\u{27E7}"),
+            "grouped IBAN not redacted: {out}"
+        );
+        assert!(!out.contains("PHONE"), "grouped IBAN mislabeled as phone: {out}");
+        assert!(!out.contains("DE89"), "leading IBAN group leaked: {out}");
+        assert_eq!(reds.iter().filter(|r| r.kind == "IBAN").count(), 1);
+        assert_eq!(reds.iter().filter(|r| r.kind == "PHONE").count(), 0);
+    }
+
     #[test]
     fn redacts_phone_numbers() {
         let cases = [